Modified lignin and separation methods

Abstract

A method of processing a lignocellulosic feedstock includes heating the lignocellulosic feedstock in a solvent mixture comprising an acid and at least 80% by volume of n-butanol to produce a reaction mixture including a butylated lignin. A butylated lignin product wherein at least 85% of the β-O-4 linkages include n-butyl ether groups can be prepared. Cellulose and butylated hemicellulose products can also be obtained.

Description

FIELD OF THE INVENTION[0001]The present invention relates to the processing of lignocellulosic biomass to provide useful products, in particular but not exclusively to the production of a modified lignin that is suitable for further processing towards useful products. Cellulose and hemi-cellulose products are also provided.BACKGROUND TO THE INVENTION[0002]Lignocellulosic biomass, which comprises cellulose, hemicellulose and lignin is the most abundant source of renewable carbon on the planet and has recently received a lot of attention as a potential source of energy, fuels and chemicals.[0003]Whilst energy, in the form of heat or electricity, can be obtained by simply burning lignocellulosic biomass, the economically viable production of liquid fuels and chemicals from such biomass will require the implementation of high efficiency bio-refineries to produce a range of renewable products.[0004]Amongst attractive bio-refinery products is cellulosic ethanol which can be produced from ...

AI Technical Summary

Benefits of technology

[0017]The production of a butylated lignin by the methods described herein has been found to produce a reaction mixture from which good quality lignin, cellulose and hemicellulose products may be readily obtained as described further hereafter. With some feedstocks, especially woody feedstocks, the method has been found to provide improved results in comparison with more conventional organosolv processes that typically make use of ethanol. Non-woody feedstocks such as grass derived feedstocks can also be processed successfully (for example rice husks). As n-butanol is a product obtainable from biomass sources, as an alternative to ethanol, the use of n-butanol in processing a lignocellulosic feedstock is convenient. A biomass processing facility may include production of n-butanol from fermentation processes of products derived from the lignocellulosic feedstock.

[0057]As with the methods of the invention providing a butylated lignin the process can provide improved cellulose, lignin and hemicellulose products. The processes described herein for the manufacture of the butylated lignin and corresponding cellulose and hem icellulose products may equally be employed for the ethylated lignin, and its corresponding products, except for the heating step described above—where the closed system is required to give an elevated temperature in comparison with ethanol or ethanol / water reflux temperatures.

Problems solved by technology

Unfortunately, the harsh conditions that are often employed lead to extensive structural modification of the lignin components which makes them difficult to valorise, especially by selective depolymerisation to aromatic monomers.

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